# Message #3057

From: David Reens <dave.reens@gmail.com>

Subject: Introduction

Date: Tue, 27 Jan 2015 21:06:54 -0700

Hi fellow 4D puzzlers!

I’m a 26 year old physics grad student in Boulder Colorado USA.

My first cubing experience was at age 6 when I rearranged the stickers by cheating during an extended family thanksgiving celebration and then felt guilty for years after everyone thought I did it legitimately and bragged about my wits etc. Later I solved it for real, two reels on my own and then looked up some algorithms.

I got into the 4D cube because my good friend is a math postdoc in topology, we took point set topo together in undergrad (i’m also a math theory major) and he is considering trying to “make” a physical 4D cube to help explain his research to people.

At first I was excited about the possibility of having to invent new algorithms for the 4D cube, but I ended up finding that I could solve it entirely using algorithms I already know for the 3D cube. In this sense I was slightly disappointed, although it was a very fun challenge to think through how to apply the algorithms I do know in the proper way.

I’m curious if anyone solved it the same way I did:

-Get one entire 3x3x3 “face” just on instinct, ignoring the connected cubies.

-Solve the connected cubies by rearranging the solved face the same way one rearranges a 3x3x3 cube. Now one entire 3x3x3x1 block of the hypercube is correct.

-Solve the second “middle reel” 3x3x3x1 block by using the algorithm for switching an edge on the middle for an edge on the bottom on the 3x3x3 cube. It works the same except it moves a 3x1 stick on the hypercube instead of a single edge. Now one entire 3x3x3x2 block of the hypercube is correct.

-Solve the “bottom face” of the hypercube, but not the connected cubies. Do this by using edge and corner swaps and rotations one would use for the 3x3x3 cube bottom reel, but again with sticks of 3 on the hypercube.

-Solve the connected cubies to the bottom face, just like a normal cube, but with an exciting twist! You have to do a 3x3x3 cube move, then rotate the bottom face in 4D any way you like, then do the inverse of the 3x3x3 cube move, or else you ruin the rest of your work. Its like doing a normal 3x3x3, but only in pairs of an algorithm and its inverse, with a change of cube orientation in between.

I’m sorry if I didn’t explain that with usual terminology.

Goodnight all, great to meet you,

Dave